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Finding the Third Proportional to 391.50 and 865.69

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Solution

The third proportional to 391.50 and 865.69 is: 1,914.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.50 : 865.69 = 865.69 : x
  2. Step 2: Convert to fraction form
    391.50/865.69 = 865.69/x
  3. Step 3: Cross multiply
    391.50x = 865.69 × 865.69
  4. Step 4: Simplify right side
    391.50x = 749,414.85
  5. Step 5: Solve for x
    x = 749,414.85/391.50
  6. Step 6: Final answer
    x = 1,914.21

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Why These Related Problems?

These problems maintain the same ratio (2.21) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.